In recent years, many semiconductor memory devices have been proposed in which memory cells are three-dimensionally arranged in order to increase the degree of integration of a memory.
Similarly to a conventional semiconductor memory device having a planar structure according to the related art, the above-mentioned semiconductor memory device requires a capacitive element (capacitor). The capacitive element is used to boost a power supply voltage or it is used as a protection element. It is necessary to reduce the occupied area of the capacitive element, similarly to a memory cell.